Method for producing polymer

Abstract

[Problem] To provide a method for producing a polymer having good separability between a poor solvent and the polymer. [Solution] A method for producing a polymer according to the present invention is characterized by including: a step for preparing a crude resin (A') which includes impurities and a polymer (A) having a repeating unit containing a phenolic hydroxyl group; and a purification step including steps (1)-(5), namely (1) a step for preparing a solution (C) which includes the crude resin (A') and a good solvent (B) in a device (X) having a stirring blade, (2) a step for subsequently feeding a poor solvent (D) into the device (X) in a state in which the solution (C) is not being stirred and acquiring a mixed solution, (3) a step for subsequently stirring the mixed solution in the device (X) with the stirring blade, (4) a step for subsequently stopping the stirring and separating the mixed solution into a poor solvent layer and a polymer layer, and (5) a step for subsequently removing the separated poor solvent layer to acquire the polymer layer.

Description

Polymer manufacturing method

[0001] The present invention relates to a method for producing polymers having repeating units containing phenolic hydroxyl groups, and more particularly to a purification step for removing low molecular weight components after producing a polymer from monomers.

[0002] Polymers containing repeating units with phenolic hydroxyl groups have long been used in a wide variety of applications. They are particularly popular in photolithography applications using 248 nm far-ultraviolet light as a light source. During polymer production, it is preferable to thoroughly remove residues of low molecular weight monomers and polymerization initiators, and to ensure that the polymer is free from metal, acid, base, and ionic impurities. Polymer production involves a polymerization step in which a monomer containing the corresponding phenolic hydroxyl group, or a monomer with a protecting group attached to the phenolic hydroxyl group, is copolymerized with a suitable commomer, followed by a purification step to remove low molecular weight components. If a monomer with a protecting group is used, a deprotection step is added to remove the protecting group from the polymer. In this case, the production process proceeds either in the order of polymerization, purification, and deprotection, or polymerization, deprotection, and purification. For the purification step, formulations involving repeated reprecipitation using a nonpolar hydrocarbon as a poor solvent have been published. (Patent Document 1)

[0003] Japanese Patent Publication No. 2009-024122

[0004] Traditionally, the reprecipitation process has involved using large amounts of poor solvent, prioritizing ease of operation. However, in recent years, with the trend towards reducing environmental impact, lowering manufacturing costs, and efficiently utilizing manufacturing equipment, there is a need to design processes that reduce the amount of poor solvent used in the reprecipitation process.

[0005] On the other hand, reducing the amount of poor solvent used for reprecipitation improves solvent efficiency and kettle efficiency, but the number of reprecipitation cycles required to achieve the same polymer purity as before increases, extending the working time. Furthermore, under reprecipitation conditions with reduced poor solvent, the polymer precipitate may become solution-like, resulting in insufficient separation of the poor solvent and the polymer. This problem is particularly pronounced when the manufacturing equipment has a large capacity of 100 L or more. Moreover, the inventors have newly discovered a problem in which, when purifying polymers using the above-mentioned poor solvent, under certain conditions, an emulsion-like layer (hereinafter also referred to as the "intermediate layer") forms between the poor solvent and the polymer for a long time, making the separation of the polymer difficult.

[0006] Therefore, the object of the present invention is to provide a method for producing polymers in which the separation of the poor solvent and the polymer solution is good, even when using a small amount of poor solvent.

[0007] As a result of diligent research, the present inventors have found that the above problem can be solved by adding a poor solvent to the polymer solution at a specific timing in the process of purifying a polymer having repeating units containing phenolic hydroxyl groups.

[0008] In other words, the present invention provides the following invention.

[0009] [1] A method for producing a polymer (A) having repeating units containing phenolic hydroxyl groups, comprising the steps of: preparing a crude resin (A') containing the polymer (A) having repeating units containing phenolic hydroxyl groups and impurities; and the following steps (1) to (5): (1) preparing a solution (C) containing the crude resin (A') and a good solvent (B) in a device (X) having a stirring blade; (2) subsequently adding a poor solvent (D) to the device (X) without stirring the solution (C) to obtain a mixture; (3) subsequently stirring the mixture in the device (X) with a stirring blade; (4) subsequently stopping the stirring to separate the mixture into a poor solvent layer and a polymer layer; and (5) subsequently removing the separated poor solvent layer to obtain a polymer layer. [2] The method for producing the polymer according to [1], wherein the ratio of the volume of the device (X) to the volume of the solution (C) is 2.5 or more and 4.0 or less. [3] The manufacturing method according to [1] or [2], wherein the amount of the poor solvent (D) added in step (2) is 80 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the solution (C). [4] The manufacturing method according to any one of [1] to [3], wherein the good solvent (B) comprises at least one selected from the group consisting of acetone, methyl ethyl ketone, methanol, isopropanol, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, ethyl acetate, butyl acetate and methyl tert-butyl ether, and the poor solvent (D) comprises at least one selected from the group consisting of methylcyclohexane, hexane and toluene. [5] The stirring power in step (3) is 0.1 kW / m ３ The above is 2.0 kW / m ３The manufacturing method according to any one of [1] to [4], wherein the proportion of repeating units containing the phenolic hydroxyl group is 80 mol% or less of the entire polymer (A), the manufacturing method according to any one of [1] to [5], wherein the proportion of repeating units containing the phenolic hydroxyl group is 80 mol% or less of the entire polymer (A), the manufacturing method according to any one of [1] to [6], comprising the following steps (1-1) to (1-5) between step (1) and step (2): (1-1) adding an acidic aqueous solution (D2) containing an acidic compound into the apparatus (X) to obtain a mixture, (1-2) subsequently adding a poor solvent (D) into the apparatus (X), (1-3) subsequently stirring the mixture in the apparatus (X) with a stirring blade, (1-4) subsequently stopping the stirring and separating the mixture into a poor solvent layer and a polymer layer, and (1-5) subsequently removing the separated poor solvent layer to obtain a polymer layer. [8] The method for producing the polymer according to [7], wherein the acidic aqueous solution (D2) is added in such a way that the acidic compound is present in an amount of 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polymer (A). [9] The method for producing the polymer according to [7] or [8], wherein the acidic compound is an organic acid.

[10] The method for producing the polymer according to any one of [7] to [9], wherein the acidic compound is an acid with a pKa of 0 or more.

[11] The method for producing the polymer according to any one of [7] to

[10] , wherein the acidic compound is a divalent or higher acid.

[12] The method for producing the polymer according to any one of [1] to

[11] , further comprising the following steps (6) to (7) following step (5): (6) Adding a good solvent (B), stirring, and redissolving the separated polymer; (7) Repeating steps (2) to (5) once or more times.

[13] The repeating unit of the polymer (A) containing a phenolic hydroxyl group is the following general formula (1) (In general formula (1), R １１ R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkyl halogen having 1 to 5 carbon atoms. １２ is a single bond or a divalent linking group. Ar is a (n) bond with 6 to 18 carbon atoms. １１ +n １２ It is a +1) valent aromatic ring group. １３ This is a chain alkyl group having 1 to 10 carbon atoms, an alkoxy group, a cycloalkyl group, an acyl group, or a halogen atom.１１ is an integer of 1 to 3. n １２ is an integer of 0 to 4.) The production method according to any one of [1] to

[12] , comprising a repeating unit represented by the formula.

[0010] According to the production method of the present invention, when producing a polymer, generation of an intermediate layer can be prevented while reducing the usage amount of a solvent, and the problem that the polymer layer and the poor solvent layer do not separate can be prevented. Thereby, the time for separating the polymer during purification of the polymer can be shortened, and the production efficiency of the polymer can be improved.

[0011] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. It should be understood that appropriate modifications and improvements made to the following embodiments by a person skilled in the art based on common knowledge without departing from the spirit of the present invention also fall within the scope of the present invention.

[0012] [Method for Producing Polymer] The method for producing a polymer (A) having a repeating unit containing a phenolic hydroxyl group according to the present invention comprises: a step of preparing a crude resin (A') containing the polymer (A) having a repeating unit containing a phenolic hydroxyl group and impurities; and the following steps (1) to (5): (1) a step of preparing a solution (C) containing the crude resin (A') and a good solvent (B) in an apparatus (X) having a stirring blade, (2) a subsequent step of charging a poor solvent (D) into the apparatus (X) without stirring to obtain a mixed liquid, (3) a subsequent step of stirring the mixed liquid in the apparatus (X) with the stirring blade, (4) a subsequent step of stopping stirring to allow separation into a poor solvent layer and a polymer layer, (5) a subsequent step of removing the separated poor solvent layer to obtain a polymer layer, wherein the method comprises a purification step including the above steps. Hereinafter, each step of the production method of the present invention will be described.

[0013] [Step of Preparing Crude Resin (A')] This step is a step of preparing a crude resin (A'). The method for preparing the crude resin (A') used in the production method of the present invention is not particularly limited. The crude resin (A') may be produced and prepared by the steps described below, or may be prepared by obtaining an already produced crude resin (A').

[0014] [Polymer (A)] The polymer (A) purified in the present invention has repeating units containing at least a phenolic hydroxyl group. (Repeating units containing a phenolic hydroxyl group) The repeating units containing a phenolic hydroxyl group are preferably of the following general formula (1) [In general formula (1), R １１ R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkyl halogen having 1 to 5 carbon atoms. １２ n is a divalent linking group which may have a single bond or a heteroatom. １１ R is an integer between 1 and 3. １３ These may be the same or different, and are a chain alkyl group, alkoxy group, cycloalkyl group, acyl group, or halogen atom having 1 to 10 carbon atoms. １２ is an integer from 0 to 4. Ar is a carbon atom with 6 to 18 carbon atoms, (n １１ +n １２ It contains repeating units derived from the structure represented by [+1) valency aromatic ring group], and more preferably consists of repeating units derived from the structure represented by the general formula (1).

[0015] In general formula (1), R １１ This is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Preferably, it is a hydrogen atom, a C1-C5 alkyl group, or a fluorinated alkyl group, more preferably a hydrogen atom, a methyl group, or a trifluoromethyl group, and even more preferably a hydrogen atom or a methyl group.

[0016] R １２ R is a single bond or a divalent linking group. The divalent linking group is not particularly limited, but examples include divalent hydrocarbon groups, *-C(=O)-O-, *-C(=O)-, *-O-C(=O)-O-, *-O-, *-C(=O)-NH-, and combinations thereof. * is the polymer main chain or the bond to the divalent hydrocarbon group. The hydrocarbon group may be a linear alkylene group, a cyclic alkylene group, an aromatic group, or a combination thereof, and some of the hydrogen atoms of the hydrocarbon group may be replaced by halogen atoms. The total number of carbon atoms of the hydrocarbon group is preferably 1 to 10, more preferably 1 to 6. Among the above, R １２Preferred examples of include a single bond, *-C(=O)-O-, *-C(=O)-, *-O-C(=O)-O-, *-C(=O)-NH-, a linear or cyclic alkylene group having 1 to 10 carbon atoms, or a combination thereof, and a single bond and *-C(=O)-O- are more preferred.

[0017] Ar is an (n １１ +n １２ +1)-valent aromatic ring group having 6 to 18 carbon atoms. Specific examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a pyrene ring.

[0018] R １３ is a linear alkyl group having 1 to 10 carbon atoms, an alkoxy group, a cycloalkyl group, an acyl group, or a halogen atom, and when n １２ is 2 or more, a plurality of R １３ may be the same or different. Specific examples include, but are not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group, an acetyl group, a chlorine atom, a bromine atom, and an iodine atom.

[0019] n １２ is an integer of 0 to 4, preferably an integer of 0 to 3. n １１ is an integer of 1 to 3.

[0020] Specific examples of the repeating unit represented by Formula (1) are shown below.

[0021]

[0022] More preferred repeating units containing a phenolic hydroxyl group are repeating units derived from hydroxystyrene or hydroxyphenyl (meth)acrylate. Still more preferred are repeating units derived from p-hydroxystyrene or p-hydroxyphenyl (meth)acrylate.

[0023] (Other Repeating Units) Polymer (A) may contain other repeating units in addition to repeating units containing phenolic hydroxyl groups. When polymer (A) is used for resist applications, it may contain various repeating units that provide the necessary performance as a resist, and it is particularly preferable to include repeating units having acid-dissociable groups.

[0024] An acid-dissociable group is a group whose structure can be cleaved by the action of an acid, at least some of the bonds in that group. When an acid-dissociable group in a polymer is dissociated by the action of an acid, it generates alkali-soluble groups such as carboxyl groups and phenolic hydroxyl groups, which changes the solubility of the polymer in photolithography developer. Examples of acid-dissociable group structures include alkali-soluble groups such as carboxyl groups and phenolic hydroxyl groups that are protected by groups having tertiary carbon atoms or acetal groups. Various acid-dissociable group-containing monomers used in known resist polymers can be used without limitation as monomers that provide repeating units having acid-dissociable groups. In addition, various monomers used in known resist polymers can be used to adjust substrate adhesion, etching resistance, and solubility in resist solvents and lithography developers. For example, 2-hydroxyethyl (meth)acrylate, 3-hydroxy-1-adamantyl methacrylate, γ-butyrolactone-α-(meth)acrylate, norbornane lactone (meth)acrylate, 2-methacryloyloxyacetoxy-4,5-oxathiatricyclo[4.2.1.0 ３，７ Examples include monomers having polar groups such as nonane-5,5-dioxide; styrene monomers such as styrene, 2-vinylnaphthalene, and vinylanthracene; (meth)acrylic acid ester monomers such as methyl (meth)acrylate and 1-adamantyl (meth)acrylate; and norbornene monomers such as norbornene, tricyclodecene, and tetracyclododecene. Indene and acenaphthylene can also be copolymerized.

[0025] When the polymer (A) is a copolymer, the proportion of repeating units containing phenolic hydroxyl groups in the polymer (A) is not particularly limited from the viewpoint of promoting rapid elimination of the intermediate layer by adding the poor solvent (D) without stirring, and may be appropriately selected depending on the use of the polymer (A) and the like from the viewpoint of preparation of the polymer (A) and the solution (C).

[0026] The proportion of repeating units containing phenolic hydroxyl groups in the polymer (A) used in the method of the present invention is not particularly limited as described above, and may be 100 mol% relative to the entire polymer (A). However, when the polymer (A) is a copolymer, the proportion of repeating units containing phenolic hydroxyl groups in the polymer (A) may be 90 mol% or less relative to the entire polymer (A), and the method can be suitably used for polymers having 80 mol% or less of repeating units containing phenolic hydroxyl groups. Among these, the method can be more suitably used for polymers having 75 mol% or less of repeating units containing phenolic hydroxyl groups, and is particularly more suitably used for polymers having 70 mol% or less of repeating units containing phenolic hydroxyl groups, which are prone to troubles caused by the generation of an intermediate layer. The lower limit of the proportion of repeating units containing phenolic hydroxyl groups in the polymer (A) is not particularly limited, and may be, for example, 20 mol% or more, 25 mol% or more, 30 mol% or more, 35 mol% or more, 40 mol% or more, 45 mol% or more, 50 mol% or more, 55 mol% or more, or 60 mol% or more relative to the entire polymer (A).

[0027] If polymer (A) is a copolymer, the lower limit of the proportion of repeating units other than repeating units containing phenolic hydroxyl groups in polymer (A) may be, for example, 10 mol% or more, 20 mol% or more, 25 mol% or more, or 30 mol% or more, relative to the entire polymer (A). The upper limit of the proportion of such other repeating units may be, for example, 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, 60 mol% or less, 55 mol% or less, 50 mol% or less, 45 mol% or less, or 40 mol% or less, relative to the entire polymer (A).

[0028] Furthermore, if there are two or more types of such other repeating units, the proportion of these other repeating units is the total proportion of these other repeating units to the entire polymer (A).

[0029] When polymer (A) is a copolymer, the proportion of repeating units having acid-dissociable groups in polymer (A) may be 10 mol% or more, 15 mol% or more, or 20 mol% or more, relative to the entire polymer (A). The upper limit may be 40 mol% or less, 35 mol% or less, or 30 mol% or less, relative to the entire polymer (A).

[0030] When polymer (A) is a copolymer, the proportion of repeating units derived from styrene monomers in polymer (A) may be 0 mol% or more, 1 mol% or more, or 3 mol% or more, relative to the entire polymer (A). The upper limit may be 10 mol% or less, or 8 mol% or less, relative to the entire polymer (A).

[0031] As an example, if polymer (A) is a copolymer, polymer (A) preferably contains repeating units containing phenolic hydroxyl groups and repeating units having acid-dissociable groups, and may further contain repeating units derived from styrene monomers. The proportion of repeating units in the polymer (A) is preferably such that the total of repeating units containing phenolic hydroxyl groups, repeating units having acid-dissociable groups, and repeating units derived from styrene monomers is 100 mol%, and the proportion of repeating units containing phenolic hydroxyl groups may be, as a lower limit, 20 mol% or more, 25 mol% or more, 30 mol% or more, 35 mol% or more, 40 mol% or more, 45 mol% or more, 50 mol% or more, 55 mol% or more, 60 mol% or more, and as an upper limit, 80 mol% or less, 75 mol% or less, or 70 mol% or less. The proportion of repeating units having acid-dissociable groups may be, as a lower limit, 10 mol% or more, 15 mol% or more, 20 mol% or more, and as an upper limit, 40 mol% or less, 35 mol% or less, or 30 mol% or less. The proportion of repeating units derived from styrene monomers may be, as a lower limit, 0 mol% or more, 1 mol% or more, or 3 mol% or more, and as an upper limit, 10 mol% or less, or 8 mol% or less. In a preferred embodiment of the present invention, the total of repeating units containing phenolic hydroxyl groups, repeating units having acid-dissociable groups, and repeating units derived from styrene monomers is set to 100 mol%, the proportion of repeating units containing phenolic hydroxyl groups is 50 mol% or more and 80 mol% or less, the proportion of repeating units having acid-dissociable groups is 10 mol% or more and 40 mol% or less, and the proportion of repeating units derived from styrene monomers is 1 mol% or more and 10 mol% or less.

[0032] Furthermore, the polymer (A) obtained by the manufacturing method of the present invention is preferably a polymer for resist compositions.

[0033] The weight-average molecular weight of polymer (A) obtained by the manufacturing method of the present invention is preferably 1,000 or more and 100,000 or less. When the weight-average molecular weight is within the above numerical range, polymer (A) has excellent resist properties when used in a resist composition.

[0034] (Polymerization Process) When preparing the crude resin (A') used in the manufacturing method of the present invention, it can be produced by polymerizing a monomer containing phenolic hydroxyl groups alone or directly with a monomer copolymerizable thereto, or by polymerizing a monomer in which the phenolic hydroxyl groups are protected by a protecting group instead of the monomer having phenolic hydroxyl groups, and then deprotecting the protecting group of the phenolic hydroxyl groups. The mode of the polymerization reaction is not particularly limited, but conventionally known polymerization methods such as radical polymerization, cationic polymerization, and living anionic polymerization can be applied.

[0035] In the radical polymerization method, monomers, radical polymerization initiators, and optionally chain transfer agents are dissolved in a solvent and heated and stirred, preferably under an inert gas atmosphere such as nitrogen. For example, this can be carried out by a so-called batch polymerization method in which all raw materials such as monomers, polymerization initiators, and chain transfer agents are dissolved in a solvent and heated to the polymerization temperature; a method in which monomers are dissolved in a solvent and heated to the polymerization temperature before adding the polymerization initiators; or a so-called dropwise polymerization method in which a solution of monomers and polymerization initiators dissolved in a solvent is added dropwise to a solvent heated to the polymerization temperature. Among these, the dropwise polymerization method is preferred because it offers high reproducibility for each production lot, and can also be carried out by a so-called independent dropwise method in which the monomers and polymerization initiators, which are radical sources, are added dropwise separately. The monomers, polymerization initiators, and chain transfer agents can also be partially supplied to the polymerization system in advance. In the dropwise polymerization method, the monomer concentration and radical concentration within the polymerization system can be adjusted by changing the composition of the supplied monomer solution and the supply speed of the monomer solution and polymerization initiator, thereby controlling the dispersion and compositional distribution of the resulting polymer.

[0036] Conventional radical polymerization initiators, such as azo polymerization initiators and peroxide polymerization initiators, can be used. Specific examples of azo polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 1,1'-azobis(cyclohexane-1-carbonitride), and 4,4'-azobis(4-cyanovaleric acid). Azo compound polymerization initiators are preferred due to their superior handling safety. Specific examples of peroxide-based polymerization initiators include decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, bis(3,5,5-trimethylhexanoyl) peroxide, succinate peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxypivalate, and 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate. These polymerization initiators can be used individually or in combination. The amount of polymerization initiator used can be selected according to the target molecular weight, the type of monomer, polymerization initiator, chain transfer agent, solvent, structural unit composition, polymerization temperature, and dropping rate.

[0037] As a chain transfer agent, known chain transfer agents can be used as needed. Among these, thiol compounds are preferred, and a wide range of known thiol compounds can be selected. Specifically, examples include t-dodecyl mercaptan, mercaptoethanol, mercaptoacetic acid, and mercaptopropionic acid. Furthermore, thiol compounds having a structure in which a 2-hydroxy-1,1,1,3,3,3-hexafluoro-2-propyl group is bonded to a saturated aliphatic hydrocarbon are particularly preferred because they have the effect of suppressing roughness and defects in the lithography pattern. The amount of chain transfer agent used can be selected according to the target molecular weight, the type of monomer, polymerization initiator, chain transfer agent and solvent, the structural unit composition, polymerization temperature and dropping rate, etc.

[0038] The solvent used in the polymerization reaction is not particularly limited as long as it can stably dissolve the monomer, polymerization initiator, chain transfer agent, and the resulting polymer. Specific examples of polymerization solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, methyl amyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, and isopropanol; ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; esters such as methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, butyl acetate, and methyl propionate; ether esters such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as tetrahydrofuran, 1,4-dioxane, and ethylene glycol dimethyl ether; aromatic hydrocarbons such as toluene and xylene; and N,N-dimethylformamide, acetonitrile, and chloroform.

[0039] These polymerization solvents can be used individually or in combination of two or more. Alternatively, monomers, polymerization initiators, chain transfer agents, and compounds with high solubility and high boiling points of the resulting polymer, such as ethylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methyl-1-butyl acetate, ethyl 3-ethoxypropionate, γ-butyrolactone, diethylene glycodimethyl ether, N-methylpyrrolidone, and dimethyl sulfoxide, may be used in combination.

[0040] There are no particular restrictions on the amount of polymerization solvent used, but if the amount of solvent used is too little, monomers may precipitate or the viscosity may become too high, making it impossible to maintain a uniform polymerization system. If the amount is too much, the monomer conversion rate may be insufficient or the molecular weight of the polymer may not be increased to the desired value. Typically, the amount of solvent is 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass, per 1 part by mass of monomer.

[0041] In the dropwise polymerization method, the amount of solvent initially added to the reaction vessel (hereinafter sometimes referred to as the initial solvent) should be at least the minimum amount required for stirring. However, if it is excessively large, the amount of monomer solution that can be supplied will decrease, potentially reducing production efficiency. Typically, the initial solvent is selected from a range of 1 / 30 or more, preferably 1 / 20 to 1 / 2, and particularly preferably 1 / 10 to 1 / 3, relative to the final charge (i.e., the total amount of the initial solvent, the monomer solution to be added dropwise, and the initiator solution), in terms of volume ratio. It is also possible to pre-mix a portion of the monomer into the initial solvent.

[0042] In dropwise polymerization, if the dropping time is too short, there is a risk of broad dispersion and a decrease in the temperature of the polymerization solution due to the large amount of solution being added at once. Conversely, if the dropping time is too long, there is a risk of the polymer being subjected to excessive heat history and a decrease in productivity. Therefore, the dropping time is usually selected from a range of 0.5 to 24 hours, preferably 1 to 12 hours, and particularly preferably 2 to 8 hours.

[0043] Furthermore, after the dropwise addition is complete, and after the temperature has been raised to the polymerization temperature in the batch heating method, it is preferable to maintain the temperature for a certain period of time or raise the temperature further to allow the remaining unreacted monomers to react. If the maturation time is too long, the production efficiency per unit of time may decrease, and the polymer may be subjected to more heat history than necessary. Therefore, it is usually selected from within 12 hours, preferably within 6 hours, and particularly preferably within 1 to 4 hours.

[0044] The polymerization temperature can be appropriately selected depending on the boiling points of the solvent, monomers, chain transfer agents, and the half-life temperature of the polymerization initiator. Polymerization may not proceed well at low temperatures, and if the temperature is set too high, there will be problems in terms of the stability of the monomers and polymers. Therefore, it is preferably selected in the range of 40 to 160°C, and particularly preferably 60 to 120°C. The polymerization temperature greatly affects the molecular weight and copolymer composition of the polymer, so it is preferable to control it. On the other hand, polymerization reactions are generally exothermic reactions, and the polymerization temperature tends to rise, making it difficult to control to a constant temperature. For this reason, in the present invention, it is preferable to include at least one compound having a boiling point close to the target polymerization temperature as the polymerization solvent, and to set the polymerization temperature to be above the initial boiling point of the compound at the polymerization pressure. According to this method, the rise in polymerization temperature can be suppressed by the latent heat of vaporization of the polymerization solvent.

[0045] The polymerization pressure is not particularly limited and may be atmospheric pressure, pressurized pressure, or reduced pressure, but is usually atmospheric pressure. In the case of radical polymerization, nitrogen gas is generated when radicals are generated from the initiator, and in the case of azo polymers, nitrogen gas is generated. Therefore, in order to suppress fluctuations in polymerization pressure, it is preferable to carry out the polymerization in an open system at or near atmospheric pressure.

[0046] (Deprotection step) When polymerization is carried out using monomers in which the phenolic hydroxyl group is protected by a protecting group as a repeating unit containing a phenolic hydroxyl group, a deprotection step is performed to remove the protecting group and expose the phenolic hydroxyl group. The deprotection reaction can be carried out by known methods. For example, when the protecting group is an acetyl group, a deprotection reaction using a base catalyst is preferred, while when the protecting group is an acetal group, a deprotection reaction using an acid catalyst is preferred. However, if polymer (A) has a structure that decomposes with an acid or base, such as a repeating unit having an acid-dissociable group or a repeating unit having a lactone structure, attention must be paid to the strength and type of acid or base used and the reaction temperature.

[0047] (Purification Step) The crude resin (A') used in the present invention contains impurities such as solvent, unreacted monomers, oligomers, and reaction by-products. Purification is performed to remove these impurities or to obtain a polymer with a desired degree of dispersion. The manufacturing method of the present invention is characterized by including the following steps (1) to (5): (1) preparing a solution (C) containing the crude resin (A') and a good solvent (B) in a device (X) having a stirring blade; (2) subsequently adding a poor solvent (D) to the device (X) without stirring the solution (C) to obtain a mixture; (3) subsequently stirring the mixture in the device (X) with a stirring blade; (4) subsequently stopping the stirring to separate the mixture into a poor solvent layer and a polymer layer; and (5) subsequently removing the separated poor solvent layer to obtain a polymer layer.

[0048] (1) Preparation step of solution (C) containing crude resin (A') and good solvent (B) This step is to prepare a solution (C) containing crude resin (A') and good solvent (B) in a device (X) having a stirring blade. The method of preparing the solution (C) in the device is not particularly limited, and a pre-prepared solution (C) may be transferred to the device, or either the crude resin (A') or the good solvent (B) may be transferred to the device in advance, and then the other may be transferred to prepare the solution (C). The pre-prepared solution may be the polymerization solution obtained in the polymerization step described above, or a solution obtained by subjecting this polymerization solution to appropriate treatment such as dilution, concentration, or filtration. In particular, if a solvent that is not a good solvent is used as the polymerization solvent, it is preferable to add the good solvent (B) or replace the solvent with the good solvent (B) in the dilution or purification treatment described above.

[0049] (Good solvent (B)) The good solvent (B) is not particularly limited as long as it is a solvent that can dissolve the polymer and separate from the poor solvent in this process, and for example, the solvent used in the polymerization process or deprotection process described above may be used as is. Specific examples of good solvents (B) include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, methyl amyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, and isopropanol; ether alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; esters such as methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, butyl acetate, and methyl propionate; ether esters such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, and methyl tert-butyl ether; and N,N-dimethylformamide, acetonitrile, and chloroform. Among these, alcohols, ethers, ketones, and esters are preferred in consideration of the solubility of polymer (A). More preferably, the solvent comprises at least one selected from the group consisting of acetone, methyl ethyl ketone, methanol, isopropanol, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, ethyl acetate, butyl acetate, and methyl tert-butyl ether. Even more preferably, the solvent comprises at least one selected from the group consisting of acetone, methyl ethyl ketone, methanol, isopropanol, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, ethyl acetate, butyl acetate, and methyl tert-butyl ether. These solvents can be used individually or in combination of two or more.

[0050] The amount of polymer (A) in solution (C) is not particularly limited as long as it can dissolve polymer (A) and the polymer layer and the poor solvent layer can be separated, but preferably it is 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less, relative to the total amount of solution (C). If too much organic solvent is used, the total volume of liquid will be large and operational problems may occur, and if the amount of organic solvent is too little, problems such as the solubility of polymer (A) may occur.

[0051] (Device with stirring blades (X)) The stirring blades used in this refining process are not particularly limited and known types can be used. For example, small types include flat paddle blades, inclined paddle blades, Rushton turbine blades, propeller blades, and three-blade swept-back blades, while large types include anchor blades, helical ribbon blades, screw blades, MAXBLEND® from Sumitomo Heavy Industries Process Equipment Co., Ltd., and Fullzone® from Kobe Steel Environmental Solutions Co., Ltd. The stirring tank may also be equipped with a jacket for supplying a heat transfer medium so that the temperature can be controlled during this process.

[0052] The ratio of the volume of the apparatus (X) to the volume of the solution (C) is preferably 2.5 or more and 4.0 or less.

[0053] (1-1) A step of adding an acidic aqueous solution (D2) to obtain a mixture. (1-2) A step of adding a poor solvent (D). (1-3) A step of stirring the mixture. In the method according to the present invention, before the purification of the polymer with the poor solvent (D), the method may include a step of adding an acidic aqueous solution (D2) to the solution (C) in which the polymer is dissolved in the apparatus to obtain a mixture, adding the poor solvent, and stirring the mixture. By purifying the polymer with an acidic aqueous solution, metal impurities, and if a deprotection step is performed in the preparation step, impurities such as deprotection catalysts can be removed more efficiently. The method of adding the poor solvent (D) in step (1-2) is preferably the same as in step (2) described later. That is, particularly preferably, the poor solvent (D) is added to the apparatus (X) without stirring the solution (C).

[0054] (Acidic aqueous solution (D2)) When solution (C) is purified with an acidic aqueous solution containing an acidic compound such as an inorganic acid or an organic acid, most of the above impurities can be efficiently removed from solution (C). Examples of inorganic acids include hydrochloric acid, phosphoric acid, nitric acid, and sulfuric acid. Preferably, the acid is an organic acid, and more preferably, an acid with a pKa of 0 or higher, such as carboxylic acids including formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, citric acid, and maleic acid. In particular, divalent or higher acids such as oxalic acid are preferred because they form complexes with metals and can be expected to have high metal removal performance. Other examples include sulfonic acids such as methanesulfonic acid and p-toluenesulfonic acid. If polymer (A) has a structure that is weak to acid, such as an acid-dissociable group, using a very strong acid may partially destroy the structure of the polymer, so from this viewpoint as well, carboxylic acids with a pKa of 0 or higher are preferred. The pKa of these acids shall be the value at 25°C in water unless otherwise specified. These values ​​can be found by referring to publicly available literature (for example, "Chemical Handbook" edited by the Chemical Society of Japan, published by Maruzen Publishing).

[0055] The amount of acidic aqueous solution (D2) added is not particularly limited as long as it is sufficient to remove impurities, and can be appropriately selected considering extraction efficiency and ease of operation. Preferably, the amount of acidic compound in the acidic aqueous solution should be between 0.1 parts by mass and 10 parts by mass per 100 parts by mass of polymer (A). If the amount of aqueous solution (D2) added is within the above numerical range, impurities in polymer (A) can be easily removed, and the acid itself can be quickly removed by purification.

[0056] (1-4) Separation step of the poor solvent layer and polymer layer This step is to separate the mixture after stopping the stirring. In this step, for example, the poor solvent layer and polymer layer are separated by allowing the stirred mixture to stand. In the above example, the mixture that has been allowed to stand is then separated into a poor solvent layer and a polymer layer.

[0057] (1-5) Step to obtain the polymer layer This step is to remove the poor solvent layer separated after the above step. This step removes the poor solvent layer containing the impurities, so that the impurities can be easily removed from the polymer (A). Similar to step (5), there are no particular limitations on the method for removing the poor solvent layer, and known methods such as decantation and pump separation may be used. The polymer layer separated from the poor solvent layer in this step is then subjected to the step of (2) adding the poor solvent (D) and stirring the obtained mixture.

[0058] (2) Step of adding poor solvent (D) and obtaining a mixture This step involves adding a poor solvent (D) to the polymer layer in the apparatus and obtaining a mixture. This step is characterized by adding the poor solvent (D) to the apparatus (X) without stirring the solution (C). This allows the intermediate layer, which will be described later, to be eliminated in a short time.

[0059] The inventors have found that in an embodiment in which a large amount of poor solvent is added at once to the polymer solution in the apparatus, regardless of whether or not it is stirred, the above-mentioned intermediate layer does not form. The above-mentioned embodiment of adding a large amount of poor solvent at once is possible on a small laboratory scale, but it is difficult in large-scale manufacturing facilities due to equipment limitations and safety concerns. At the same time, the inventors have found that in an embodiment in which the poor solvent is added little by little to the polymer solution in the apparatus while stirring, the intermediate layer forms over a long period of time under conditions where the amount of poor solvent used relative to the good solvent is small. To address the above problem, the inventors have found that by adding the poor solvent to the polymer solution little by little without stirring, the intermediate layer can be quickly eliminated even in large-scale manufacturing facilities where the total amount of poor solvent used is large and it is difficult to add a large amount of poor solvent at once, such as in apparatus (X) with a volume of 30 L or more.

[0060] In the manufacturing method according to the present invention, when the poor solvent is added and the resulting mixture is stirred, the stirred mixture separates into a poor solvent layer and a polymer layer after a certain period of time following the cessation of stirring. On the other hand, an intermediate layer may form during the aforementioned period following the cessation of stirring. In particular, if the poor solvent is added while stirring the mixture, the intermediate layer may continue to form for a long time after the cessation of stirring. On the other hand, if the poor solvent is added without stirring the mixture, the intermediate layer disappears in a short time after the cessation of stirring. The reason for this is unknown, but it is thought that the polymer (A), which has repeating units containing phenolic hydroxyl groups, acts as an emulsifier because it has hydrophilic and hydrophobic parts. When the poor solvent is added while stirring the mixture containing the polymer, the solubility between the solution (C) and the poor solvent (D) increases excessively, causing the intermediate layer to form for a long time. Therefore, it is presumed that by adding the poor solvent (D) to the mixture without stirring, the solution (C) and the poor solvent (D) will not become excessively compatible, and the intermediate layer will dissolve in a short time after the stirring is stopped, as described later. However, the present invention is not bound by this logic.

[0061] (Poor Solvent (D)) In the manufacturing method according to the present invention, a poor solvent is used as the solvent for purifying the polymer. When the polymer used in the present invention is a resist material, a poor solvent with an extremely low metal content is preferred.

[0062] Nonpolar poor solvents can be suitably used as the poor solvent. Examples of nonpolar poor solvents include aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. Examples of aliphatic hydrocarbons and alicyclic hydrocarbons include aliphatic hydrocarbon compounds having 5 to 16 carbon atoms, alicyclic hydrocarbon compounds having 5 to 10 carbon atoms, and aromatic hydrocarbon compounds having 6 to 10 carbon atoms. Examples include aliphatic hydrocarbons such as hexane; alicyclic hydrocarbons such as methylcyclohexane; and aromatic hydrocarbons such as toluene and xylene. Preferably, the poor solvent includes at least one selected from the group consisting of methylcyclohexane, hexane, and toluene, and more preferably, at least one selected from the group consisting of methylcyclohexane, hexane, and toluene.

[0063] The amount of poor solvent (D) added in step (2) can be appropriately selected considering extraction efficiency and operability, but the amount of poor solvent (D) added in step (2) is preferably 80 parts by mass or more and 150 parts by mass or less, and more preferably 90 parts by mass or more and 130 parts by mass or less, per 100 parts by mass of solution (C). When the amount of poor solvent is within the above numerical range, impurities are effectively removed, and the intermediate layer described later is suitably resolved in a short time. In step (3) and / or before thereafter, a good solvent (B) used in solution (C) may be further added to increase the fluidity of the polymer separated from the poor solvent (D), or from the viewpoint of adjusting the ratio of solution (C) to poor solvent (D).

[0064] The time for adding the poor solvent (D) is not particularly limited as long as the effects of the present invention are not impaired, but it can be set at an adding rate of preferably 3 minutes to 40 minutes, more preferably 5 minutes to 30 minutes, and even more preferably 8 minutes to 20 minutes.

[0065] As described above, this step involves adding the poor solvent (D) to the apparatus (X) while the solution (C) is not being stirred. However, in addition to step (2), there is no preclude adding the poor solvent (D) while the solution (C) or mixture is being stirred (for example, in step (3), etc.), as long as the effects of the present invention are not impaired. The amount of poor solvent (D) added while the solution (C) or mixture is being stirred is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, relative to the amount of poor solvent (D) added in step (2), which is 100 parts by mass. Considering the operating conditions of the manufacturing equipment, the amount of poor solvent (D) added while the solution (C) or mixture is being stirred is particularly preferably 0 parts by mass (i.e., no addition while stirring).

[0066] (3) Mixture stirring step This step involves adding a poor solvent (D) to the polymer layer in the apparatus and stirring the resulting mixture. However, if steps (1-1) to (1-5) above are not performed, this step involves adding a poor solvent (D) to the solution (C) in the apparatus and stirring the resulting mixture. Impurities such as metals contained in polymer (A) can be extracted into the poor solvent layer by this step. Also, if steps (1-1) to (1-5) above are performed, any acid remaining in the polymer can be extracted into the poor solvent layer. This makes it possible to obtain polymer (A) with fewer metal impurities and less remaining acid. In particular, in the case where polymer (A) is a polymer for resists, metal impurities that adversely affect resist performance can be efficiently removed from polymer (A). The temperature in this step can be appropriately selected considering operability and solubility, for example, 0 to 100°C, preferably around 25 to 50°C.

[0067] [Agitation Power] The agitation power is not particularly limited as long as the effects of the present invention are not impaired, but is preferably 0.1 kW / m ３ The above is preferable, and more preferably 0.2 kW / m ３ The above is true, and preferably 2.0 kW / m ３ The following, and more preferably 1.9 W / m² ３ The following applies: When the stirring power is within the above numerical range, the intermediate layer is quickly dissolved, and the poor solvent layer and polymer layer are quickly separated, allowing only the impurity layer containing impurities to be removed.

[0068] Furthermore, the above stirring power can be calculated from the measured values ​​of torque and rotational speed related to stirring, or it can be calculated based on the configuration of the stirring system, separately from the measured values ​​of torque and rotational speed. When calculating based on the configuration of the stirring system, for example, Equation (0) Equation (0) P V = N ｐ ×ρ×n ３ ×d ５ / V (here, P Ｖ This is the required stirring power per unit volume [kW / m³] ３ ] and N ｐ ρ is the power number [dimensionless], and ρ is the density [kg / m³]. ３], where n is the rotational speed [1 / s], d is the blade diameter [m], and V is the liquid volume [m] ３ ] is calculated by ). ρ depends on the properties of the mixed liquid being stirred, and n and d correspond to the operating conditions and dimensions of the device having the stirring blades. Similarly, V corresponds to the volume of the mixed liquid prepared in the device having the stirring blades. The power number Np can be a value obtained using a known estimation formula, such as Nagata's formula or Kameoka-Hirai's formula, depending on the type of stirring system.

[0069] (4) Separation step of the poor solvent layer and polymer layer This step involves separating the mixture obtained in step (3) into a poor solvent layer and a polymer layer by stopping the stirring. As a method to eliminate the intermediate layer, it is possible to perform steps to promote layer separation, such as operating the stirrer very slowly to perform fine stirring. However, according to the method of the present invention, the poor solvent layer and the polymer layer are quickly separated without performing the above-mentioned steps to promote layer separation, and the problems related to the generation of the intermediate layer described above can be solved. For this reason, the manufacturing method of the present invention can be suitably used in large-scale manufacturing facilities where it is difficult to perform the above-mentioned steps to promote layer separation.

[0070] (5) Polymer layer acquisition step This step is to remove the poor solvent layer separated from the polymer layer after the separation step. By removing the poor solvent layer, metal impurities and acids that have moved to and dissolved in the poor solvent layer can be removed. The removal method is not particularly limited, and known methods such as decantation and pump separation may be used.

[0071] The above steps can reduce the amount of impurities such as metal impurities in the polymer solution (C), but steps (2) to (5) may be repeated multiple times. That is, the manufacturing method of the present invention preferably further includes the following steps (6) to (7) following step (5): (6) Adding a good solvent (B) and stirring to redissolve the separated polymer; (7) Repeating steps (2) to (5) one or more times. In particular, if purification is performed with an acidic aqueous solution (D2), it is preferable to perform the subsequent purification with a poor solvent (D) multiple times in order to remove metal impurities and acid components. It is also preferable to perform step (6) in order to increase the fluidity of the separated polymer. Therefore, a preferred embodiment is a method in which the purification step is performed multiple times, at least the first time using an acidic aqueous solution and at least the last time using a poor solvent. The type of good solvent (B) in step (6) can be appropriately set according to the properties of the polymer and the purification process, and may be the same as or different from the good solvent (B) in step (1). Similarly, in embodiments in which steps (6) to (7) are performed multiple times, the good solvent (B) in different steps (6) may be the same or different.

[0072] [Other manufacturing processes] The polymer (A) obtained by the above processes (1) to (5) may, if necessary, be subsequently subjected to treatments such as replacing the solvent in the polymer solution with a solvent used in the resist composition, or filtering to further reduce metal impurities in the polymer or remove insoluble components.

[0073] The embodiments of the present invention will be described in detail below with reference to examples, but the present invention is not limited in any way to these examples. Unless otherwise specified in the following examples, parts are measured by mass.

[0074] The analysis in this example was performed as follows: [Weight-average molecular weight and molecular weight distribution of polymer] The weight-average molecular weight and molecular weight distribution of the polymer synthesized below were measured by GPC (gel permeation chromatography) using polystyrene as a standard. The sample used for analysis was prepared to be a tetrahydrofuran solution with a solid content concentration of 2% by mass of the polymer. The sample injection volume into the apparatus was 50 μL. Measuring apparatus: Tosoh HLC-8320GPC Detector: Differential refractive index (RI) detector Column: Shodex GPC KF804 x 3 (Showa Denko) Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min Temperature: 40°C Calibration curve: Created using a polystyrene standard sample (Tosoh) [Analysis of residual amounts of monomers and polymerization initiators during polymerization reaction and calculation method of conversion rate] In the polymerization reaction experiment below, the quantitative analysis of low molecular weight components, including monomers and polymerization initiators during the polymerization reaction, was performed by LC (liquid chromatography). Measurement device: Tosoh HLC-8320GPC Detector: Differential refractive index (RI) detector Column: Tosoh TSKgel superHZ1000 x 4 Eluent: Tetrahydrofuran Flow rate: 0.35 mL / min Temperature: 40°C The sample used for analysis was prepared to be a tetrahydrofuran solution with a polymer solid content of 2% by mass. The sample volume injected into the instrument was 50 μL.

[0075] (Abbreviations for compounds) The abbreviations for the compounds used in the following experiment are as follows: THF: Tetrahydrofuran MCH: Methylcyclohexane PACS: 4-acetoxystyrene (p-acetoxystyrene) PTBST: Para-t-butoxystyrene AIBN: 2,2'-azobisisobutyronitrile MCH: Methylcyclohexane

[0076] [Synthesis Example 1: Preparation Steps for PHS Polymer] (Polymerization Step) 100 parts by weight of a raw material solution was prepared by mixing monomer 4-acetoxystyrene, monomer styrene, monomer PTBST (para-t-butoxystyrene), solvent methyl ethyl ketone, and polymerization initiator AIBN. 25 parts by weight of the total raw material solution was added to a reactor purged with nitrogen gas and heated to 80°C. The remaining 75 parts by weight of the total raw material solution was added dropwise over 3 hours, and heating was continued for another 2 hours after the supply of the raw material solution was completed to obtain a copolymer solution. The molar ratio of the monomers was 4-acetoxystyrene / styrene / para-t-butoxystyrene / polymerization initiator = 65 / 5 / 30 / 9. The concentration of the copolymer solution was 35% by weight, and the molecular weight of the polymer was Mw = 10,000. (Deprotection step) To 100 parts by weight of polymerization reaction solution in the reactor, 50 parts by weight of methanol, 10 parts by weight of water, and 0.3 parts by weight of DBU (diazabicycloundecene base catalyst) were added, and the deprotection reaction was carried out for 2 hours under solvent reflux in a nitrogen atmosphere by immersion in a 70°C heat source. Sampling was performed. １ Analysis by 1H-NMR confirmed that 100% of the acetoxy groups in the polymer were converted to hydroxyl groups. (Base removal step) 100 parts by weight of butyl acetate was added to the polymer solution after the deprotection reaction. The solution was transferred to a separatory funnel and washed with 100 parts by weight of pure water. The organic solvent layer was concentrated under reduced pressure using an evaporator to obtain a solid content of 35%.

[0077] [Synthesis Example 2: Preparation Steps for PHS Resin] A 25% solution of 4-hydroxystyrene produced by the monomer ethylphenol dehydrogenation method (solvent: mixture of ethylphenol, methanol, and water), monomer styrene, monomer PTBST (para-t-butoxystyrene), and polymerization initiator AIBN were mixed to prepare 100 parts by weight of the raw material solution. 25 parts by weight of the total raw material solution was added to a reactor purged with nitrogen gas and heated to 80°C. The remaining 75 parts by weight of the total raw material solution was added dropwise over 3 hours, and heating was continued for another 2 hours after the supply of the raw material solution was completed to obtain a copolymer solution. The molar ratio of the monomers was 4-hydroxystyrene / styrene / para-t-butoxystyrene / polymerization initiator = 75 / 5 / 20 / 9. The concentration composition ratio of the polymerization solution was ethylphenol / methanol / water / total of monomers and polymerization initiator = 37 / 21 / 10 / 32. The molecular weight of the polymer was Mw = 10,000.

[0078] [Example 1] (First Purification) 100 g of the polymer solution synthesized in Synthesis Example 1 (main solvent: butyl acetate, solids content concentration 35%) was prepared and placed in a 1 L graduated cylinder. With a stirrer attached, a mixture of 8 g of 1% oxalic acid solution and 10 g of methanol was added to neutralize and remove the residual base used in the deprotection step. Then, stirring was stopped. With stirring stopped, 150 g of the poor solvent MCH was added dropwise to the graduated cylinder at a constant rate over 15 minutes. After the addition of the poor solvent was completed, the stirrer was started and the mixture was mixed uniformly for 30 minutes. The stirrer was stopped and the liquid was allowed to separate into layers. Observing the time taken and the height of the liquid level, after 3 minutes, there were three layers: upper, middle, and lower, with an intermediate layer visible. After 5 minutes, the lower layer was 130 ml and the upper layer was 340 ml, almost completely separated. After 10 minutes, the lower layer was 120 ml and the upper layer was 340 ml, completely separated into two layers. The upper layer was removed by suction, completing the first reprecipitation. (Second purification) Next, to increase the fluidity of the lower layer, the stirrer was started, and 5 g of methanol and 30 g of ethyl acetate were added to the lower layer remaining in the graduated cylinder and mixed. Then, the stirring was stopped. With the stirring stopped, 150 g of the poor solvent MCH was added dropwise to the graduated cylinder over 15 minutes. After the addition of the poor solvent was complete, the stirrer was started and mixed uniformly for 30 minutes. The stirrer was stopped, and the liquid layers were allowed to separate. Observing the time taken and the height of the liquid levels, after 5 minutes, the lower layer was 130 ml and the upper layer was 370 ml, indicating that the layers had almost separated. After 10 minutes, the lower layer was 120 ml and the upper layer was 370 ml, indicating complete separation into two layers. The upper layer was removed by suction, completing the second reprecipitation. (Third purification) Next, the stirrer was started and 5 g of methanol and 30 g of ethyl acetate were added to the lower layer remaining in the graduated cylinder and mixed to increase the fluidity of the lower layer. Then, the stirring was stopped. With the stirring stopped, 150 g of the poor solvent MCH was added dropwise to the graduated cylinder over 15 minutes. After the addition of the poor solvent was complete, the stirrer was started and mixed uniformly for 30 minutes. The stirrer was stopped and the liquid was allowed to separate into layers. Observing the time taken and the height of the liquid levels, it was found that after 5 minutes, the lower layer was 120 ml and the upper layer was 370 ml, with almost complete separation into two layers. After 10 minutes, the lower layer was 120 ml and the upper layer was 370 ml, with complete separation into two layers. The upper layer was removed by suction, completing the third reprecipitation.

[0079] [Comparative Example 1] (First Purification) 100 g of the polymer solution synthesized in Synthesis Example 1 (main solvent: butyl acetate, solid content concentration 35%) was prepared and placed in a 1 L graduated cylinder. With a stirrer attached, a mixture of 8 g of 1% oxalic acid solution and 10 g of methanol was added while stirring to neutralize and remove the base used in the deprotection step. Subsequently, while continuing to stir, 150 g of the poor solvent MCH was added dropwise to the graduated cylinder over 15 minutes. After the addition of the poor solvent was completed, the mixture was mixed uniformly for another 30 minutes. The stirrer was stopped and the liquid layers were allowed to separate. Observing the time taken and the height of the liquid levels, it was found that the layers had not separated after 10 minutes, and after 15 minutes, there were three layers separated: a lower layer of 40 ml, an intermediate layer of 320 ml, and an upper layer of 340 ml. After 55 minutes, the mixture consisted of a lower layer of 115 ml, an intermediate layer of 200 ml, and an upper layer of 340 ml. After another 80 minutes, the mixture had completely separated into two layers: a lower layer of 120 ml and an upper layer of 340 ml. The upper layer was removed by suction, completing the first reprecipitation. (Second purification) Next, to increase the fluidity of the lower layer, a stirrer was started, and 5 g of methanol and 30 g of ethyl acetate were added to the lower layer remaining in the graduated cylinder and mixed. Subsequently, while continuing to stir, 150 g of the poor solvent MCH was added dropwise to the graduated cylinder over 15 minutes. After the addition of the poor solvent was complete, the mixture was mixed uniformly for another 30 minutes. The stirrer was stopped, and the liquid was allowed to separate into layers. Observing the time taken and the liquid level, it was found that the mixture had not separated much after 10 minutes, and after 15 minutes, it had separated into three layers: a lower layer of 40 ml, an intermediate layer of 340 ml, and an upper layer of 360 ml. After 55 minutes, the mixture consisted of a lower layer of 100 ml, a middle layer of 240 ml, and an upper layer of 360 ml. After another 80 minutes, the mixture had completely separated into two layers: a lower layer of 110 ml and an upper layer of 360 ml. The upper layer was removed by suction, completing the second reprecipitation. (Third purification) Next, to increase the fluidity of the lower layer, a stirrer was started, and 5 g of methanol and 30 g of ethyl acetate were added to the lower layer remaining in the graduated cylinder and mixed. Subsequently, while continuing to stir, 150 g of the poor solvent MCH was added dropwise to the graduated cylinder over 15 minutes. After the addition of the poor solvent was complete, the mixture was mixed uniformly for another 30 minutes. The stirrer was stopped, and the liquid was allowed to separate into layers.Observing the time taken and the liquid level, after 10 minutes, the liquid had separated into three layers: a lower layer of 20 ml, a middle layer of 340 ml, and an upper layer of 360 ml. After 55 minutes, the liquid was separated into 100 ml, a middle layer of 260 ml, and an upper layer of 360 ml. After another 100 minutes, the liquid had completely separated into two layers: a lower layer of 110 ml and an upper layer of 360 ml. The upper layer was removed by suction, completing the third reprecipitation.

[0080] [Example 2] (First Purification) 100 g of the polymer solution synthesized in Synthesis Example 2 (concentration 32% at 100% yield) (solution composition: ethylphenol / methanol / water / total ratio of polymer, monomer and initiator = 37 / 21 / 10 / 32 wt) was prepared and placed in a 1 L graduated cylinder. A stirrer was attached. Then, with the stirring stopped, 110 g of the poor solvent MCH was added dropwise to the graduated cylinder at a constant speed over 20 minutes. After the addition of the poor solvent was complete, the stirrer was started and mixed uniformly for 20 minutes. The stirrer was stopped and the liquid was allowed to separate into layers for 20 minutes. The liquid levels were completely separated into two layers: a lower layer of 100 ml and an upper layer of 290 ml. The upper layer was removed by suction to complete the first reprecipitation. (Second purification) Next, to increase the fluidity of the lower layer, the stirrer was started and 22g of ethyl acetate and 5g of methanol were added to the lower layer remaining in the graduated cylinder and mixed. Then, the stirring was stopped. With the stirring stopped, 110g of the poor solvent MCH was added to the graduated cylinder dropwise at a constant rate over 20 minutes. After the addition of the poor solvent was complete, the stirrer was started and mixed uniformly for 20 minutes. The stirrer was stopped and the liquid was allowed to separate into layers for 20 minutes. The liquid had completely separated into two layers: 100ml of the lower layer and 300ml of the upper layer. The upper layer was removed by suction, completing the second reprecipitation. (Third to sixth purifications) Next, the exact same procedure as the second reprecipitation was repeated four more times, for a total of six reprecipitation purifications. With repeated purification, the waiting time for layer separation was 20 minutes, and two-layer separation of the upper and lower layers was achieved.

[0081] [Comparative Example 2] (First Purification) 100 g of the polymer solution synthesized in Synthesis Example 2 (concentration 32% when calculated at 100% yield) (solution composition: ethylphenol / methanol / water / total ratio of polymer, monomer and initiator = 37 / 21 / 10 / 32 wt) was prepared and placed in a 1 L graduated cylinder. A stirrer was attached. Subsequently, while stirring, 110 g of the poor solvent MCH was added dropwise to the graduated cylinder at a constant speed over 20 minutes. After the addition of the poor solvent was completed, the stirrer was kept running and the mixture was mixed uniformly for 20 minutes. The stirrer was stopped and the liquid was allowed to separate into layers for 20 minutes. The mixture separated into three layers: a lower layer of 100 ml, a middle layer of 120 ml, and an upper layer of 290 ml. After waiting for another 60 minutes, the mixture separated into two layers: a lower layer of 100 ml and an upper layer of 290 ml. The upper layer was removed by suction to complete the first reprecipitation. (Second purification) Next, to increase the fluidity of the lower layer, the stirrer was started and 22 g of ethyl acetate and 5 g of methanol were added to the lower layer remaining in the graduated cylinder and mixed. Then, while continuing to stir, 110 g of the poor solvent MCH was added dropwise to the graduated cylinder at a constant rate over 20 minutes. After the addition of the poor solvent was complete, the stirrer was started and mixed uniformly for 20 minutes. The stirrer was stopped and the liquid was allowed to separate into layers for 20 minutes. The liquid had separated into three layers: a lower layer of 80 ml, a middle layer of 160 ml, and an upper layer of 300 ml. Since the separation was insufficient, additional work was performed to promote layer separation by repeatedly rotating the stirrer very slowly and stopping it visually. After an additional hour, the liquid separated into two layers: a lower layer of 100 ml and an upper layer of 300 ml. The upper layer was removed by suction to complete the second reprecipitation. (Purification 3rd to 6th times) Next, the exact same procedure as the second reprecipitation was repeated four more times, for a total of six reprecipitation purifications. During this time, at the point 20 minutes after the stirring was stopped, three layers separated into upper, middle, and lower layers, resulting in poor separation. It was necessary to visually rotate the stirrer very slowly to promote layer separation each time. The additional work required was about 1 to 3 hours. In Comparative Example 2, the additional visual work to promote layer separation is possible on a small laboratory scale, but it is difficult to implement in large-scale manufacturing facilities because the inside of the equipment is not well visible.

[0082] Tables 1 and 2 summarize the purification conditions and layer separation results for each purification step in Examples 1 and 2 and Comparative Examples 1 and 2 described above. The evaluation results of layer separation are based on the following criteria: [Evaluation Criteria] ○: No intermediate layer required, no additional work needed △: Intermediate layer eliminated with additional work ×: Intermediate layer present

[0083] Based on the above, the manufacturing method of the present invention can prevent or quickly resolve three-layer separation. Therefore, the method of the present invention can be suitably used even in configurations using large-scale manufacturing equipment where it is difficult to add a large amount of solvent at once.

[0084]

[0085]

Claims

1. A method for producing a polymer (A) having repeating units containing phenolic hydroxyl groups, comprising the steps of: preparing a crude resin (A') containing the polymer (A) having repeating units containing phenolic hydroxyl groups and impurities; and the following steps (1) to (5): (1) preparing a solution (C) containing the crude resin (A') and a good solvent (B) in a device (X) having a stirring blade; (2) subsequently adding a poor solvent (D) to the device (X) without stirring the solution (C) to obtain a mixture; (3) subsequently stirring the mixture in the device (X) with a stirring blade; (4) subsequently stopping the stirring to separate the mixture into a poor solvent layer and a polymer layer; and (5) subsequently removing the separated poor solvent layer to obtain a polymer layer.

2. The manufacturing method according to claim 1, wherein the ratio of the volume of the apparatus (X) to the volume of the solution (C) is 2.5 or more and 4.0 or less.

3. The manufacturing method according to claim 1 or 2, wherein the amount of the poor solvent (D) added in step (2) is 80 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the solution (C).

4. The manufacturing method according to any one of claims 1 to 3, wherein the good solvent (B) comprises at least one selected from the group consisting of acetone, methyl ethyl ketone, methanol, isopropanol, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, ethyl acetate, butyl acetate, and methyl tert-butyl ether, and the poor solvent (D) comprises at least one selected from the group consisting of methylcyclohexane, hexane, and toluene.

5. The stirring power in step (3) is 0.1 kW / m ３ The above is 2.0 kW / m ３ The manufacturing method according to any one of claims 1 to 4, which is as follows:

6. The manufacturing method according to any one of claims 1 to 5, wherein the proportion of repeating units containing the phenolic hydroxyl group is 80 mol% or less with respect to the entire polymer (A).

7. A manufacturing method according to any one of claims 1 to 6, comprising the following steps (1-1) to (1-5) between step (1) and step (2): (1-1) adding an acidic aqueous solution (D2) containing an acidic compound to the apparatus (X) to obtain a mixture; (1-2) subsequently adding a poor solvent (D) to the apparatus (X); (1-3) subsequently stirring the mixture in the apparatus (X) with a stirring blade; (1-4) subsequently stopping the stirring to separate the mixture into a poor solvent layer and a polymer layer; and (1-5) subsequently removing the separated poor solvent layer to obtain a polymer layer.

8. The manufacturing method according to claim 7, wherein the acidic aqueous solution (D2) is added such that the acidic compound is present in an amount of 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polymer (A).

9. The manufacturing method according to claim 7 or 8, wherein the acidic compound is an organic acid.

10. The manufacturing method according to any one of claims 7 to 9, wherein the acidic compound is an acid with a pKa of 0 or higher.

11. The manufacturing method according to any one of claims 7 to 10, wherein the acidic compound is a divalent or higher acid.

12. A manufacturing method according to any one of claims 1 to 11, further comprising the following steps (6) to (7) following step (5): (6) adding a good solvent (B), stirring, and redissolving the separated polymer; (7) repeating steps (2) to (5) once or more times.

13. The repeating unit containing a phenolic hydroxyl group of the polymer (A) is represented by the following general formula (1) (In general formula (1), R １１ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms. R １２ represents a single bond or a divalent linking group. Ar represents an (n １１ +n １２ +1)-valent aromatic ring group having 6 to 18 carbon atoms. R １３ represents a linear alkyl group having 1 to 10 carbon atoms, an alkoxy group, a cycloalkyl group, an acyl group, or a halogen atom. n １１ is an integer of 1 to 3. n １２ is an integer of 0 to 4.) The production method according to any one of claims 1 to 12, comprising the repeating unit represented by.

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